In cable systems, such as a Hybrid Fiber Coaxial (“HFC”) network, a return can accommodate two-way connectivity for TV, Voice, and Data that is shared by several customers. A return system of the HFC network is “shared” by all of the customers, i.e., each signal from a customer site is funneled to the same node in a sequence of transmissions. The signals from each customer site, however, carry interference, e.g., noise and ingress, that can compromise the return system. In other words, the interference may enter the normally “shielded” coaxial cable thereby degrading performance of the return system. As a result, a problem at a customer site can compromise the service for all customers on that node, limiting return transmission required to support services of the HFC. However, it can be difficult and costly to determine whether the problem occurs due to a common system element or due to a problem at a customer site, especially which customer site it may be.